Thread-cutting seam opener



July 11, 195o R. H. MCMURRAY 2,514,662

THREAD CUTTING SEAM OPENER Filed Oct. l5, 1945 INVENTOR.

BY f f l/l A l,

j TORNEY.

Patented July 11, 1950 UNITED STATES PATENT OFFICE 2,514,662 1 THREAD-CUTTING sEAM OPENER- Ray H. McMurray, oakland, Calif. Application october 15, 1945,-seria1iNo. 622,319 4 Claims. (Cl..164-17.5)

Mypresent invention relates to a seam ripping device, and more particularly to an attachment Ifor sewing machines by which the threads of a Stitched seam may be exposed and progressively cut as material containing the seam isadvanced under the presser foot of the sewing machine.

An object of my invention is to provide a device for ripping machine stitched seams in which the threads of a seam are exposed and cut in a new and novel manner.

Another object of the invention -is to provide an attachment that may be applied to the operating head of a sewing machine and operated by the needle bar in conjunction with the presser Lfoot and feed thereof to cut the threads of a .machine stitched seam.

Another object of th'e -invention is to provide a device, having a reciprocating knife, that may be conveniently mounted upon the presser foot supporting bar of a sewing Vmachine and in which the knife carried thereby is driven with a reciprocating movement by an operating connection with the needle bar of the machine.

Another object of the 'invention is -to provide a machine vstitched seam opening attachment that may be mounted upon a sewing machine and driven by the `needle b'ar thereof vso as to cut the threads of a seam in timed relation with the advance of the seam carrying material under the press'er'footof the machine.

A further object of the invention is to provide a'novel arrangement of areciprocating knife and 'aA supporting means therefor havingy an anvil-like kportion over which 'the seam may be guided and parted to expose the threads of the seam to the operation ofthe knife the uncut seam is moved over the Ianvil-like portion of :the blade supporting means. y

Other objects and advantages ofrny invention will be in part evident to those skilled in the art, and in part pointed out hereinafter lin the following 'description taken in connection with the accompanying drawing, `wherein there is shown by Way of illustration and .not of .limitation a preferred embodiment thereof.

In the drawing;

Figure 1 is a fragmentary 'end view of'a 'sewing machine head of conventional construction showing a preferred form of my device mounted thereupon,

Figure 2 is a fragmentary sectional view of the device shown in Figure 1 taken along line 2 2 of Figure 1,

Figure 3 is a top view of the device Shown in .Figure .1 with the presser foot and needle bars shown inseCtiOn, y A Figure 4 .is a sectional view taken along line -d-li of Figure 1, and

Figure y5 is an yenlarged fragmentary sectional view taken along line 5--5 of Figure 4.

In Figure 1 of the drawing I have shown, for the purpose of illustrating my invention, a preferred embodiment thereof as applied to the operating head of a conventional slewing machine, here designated by the numeral I0. The operating head I0 of the sewing machine is provided with a presser foot supporting bar l I that carries a presser foot I2 at its lower end. The presser foot I2 extends over and is adapted to cooperate with a Work feeding mechanism I3 which operates to advance the work to be sewed in the path of a threaded needle (not shown) that vextends from the end of a needle bar I 4. The feeding mechanism I3, as is well understood, comprises a .series of toothed members that gyrate machine is mounted. Mounted upon the presser .foot supporting bar II by a suitable clamp, as

will hereinafter appear, there is a blade enclosing housing I6 in which there is mounted a stitch cutting blade Il. In this particular showing the blade I1 is Vmounted to move in a slightly inclined gluideway vI8 formed inthe housing I6 so that its cutting edge will be disposed at a .slight overhanging angle with respect to a seam guiding horn or anvil I9 whichprojects from the bottom of the enclosing housing I6 toward the presser foot I2. The lower fendof the housing I6 is also here shown as having an outwardly flared bottom portionwZ'll which, in conjunction with the horn or .anvil I9, will 'facilitate the spreading of a stitched seam `over the cutting edge of the blade Il so as to expose the stitching thereof'to the cutting action of the blade I1 as the latter reciprocates. As a means for imparting a vreciprocating movement from the needle bar I4 to the blade I'I, there is a walking beam 2l which is here shown as pivoted, as at 22, upon the housing I6. In order to provide for a simple and convenient mounting of the device upon a conventional sewing machine, the yenclosing housing I6 is, as is shown'in Figure 3 of the drawing, provided with a friction gripping clamp 23 that is adapted to be tightened upon the presser foot supporting bar II by a thumb screw 24, and the walking beam 2l is provided with forked ends 25 and 26 that are adapted to respectively engage with a pin 21 carried by the blade I1 and a thumb screw accommodating boss 2B upon the needle bar Ili in which a thumb screw 29 is threaded for securing a needle upon the end of the needle bar I4.

In addition to the horn or anvil I9 the device, as shown in Figure 2 of the drawing, is also provided with a downwardly depending bracket 30 which supports downwardly depending lingers 3| i and 32 that are held in spaced relation with the upper surface of the anvil or hornl I9 so as to guide a seam to be ripped over the anvil or horn I 9 as the stitched seam is advanced under the. f i presser foot I 2 by the action of the feeding mech-` anism I3. A

It is believed that the operation of my device will be apparent from the above description.Y

However, upon referring to Figure 4 of the draw` ing it will be seen that as the workshown in, dot and dash lines, is advanced over the anvil- Vorhorn I9with the seam in alignment with the blade Il, the lstitching of the seam will be parted `so, as to expose the threads thereof to the cutting-action of the knife I'I as it is reciprocated by the operation of the needle bar I4.

operation, `as is more clearly shown in Figure 5 of the drawing, the free edges of the material at the seam will be folded back upon the anvil or horn 1 I9 as the work is guided thereover by the lingers 3|I and 32. Then, as the material, with the -stitched seam, is advanced :or drawn under the 1 'f presser foot I2 and around the housing I6 by a j slight pull on the part of the operator, the seam` l'will open and the exposed stitches will be prol' gressively cut by the reciprocating blade I'I.

While I have, for the sake of clearness and inv U'considered as part of this invention.

Having thus described my invention, what I claimr and desire to secure by Letters Patent is: 1. In a seam ripping attachment for a sewing machine, the combination of a rearwardly disposed blade guiding support adapted to `be secured to the presser foot supporting bar of a sewing machine head, a blade mounted for reciprocating movement upon said guiding support, an

anvil-like horn disposed in alignment with and at i l the lower end of said blade and extending toward the presser foot upon said presser foot supporting bar over which a seam to be ripped may be moved, guide fingers carried by said blade guiding support and cooperating with said anvil-like horn for guiding the seam toward said blade, and `,a driving connection between the needle bar of the sewing machine and said blade for imparting a reciprocating movement to said blade as the seam is advanced over said anvil-like horn and by the action of said presser foot.

y 2. In a seam thread cutting device for use with a conventional sewing machine, the combination During this 4 of a sewing machine presser foot supporting bar having a presser foot at the lower end thereof, a needle bar adjacent said presser foot supporting bar, a blade enclosing housing mounted behind said presser foot supporting bar, a work supporting horn projecting from said housing toward and terminating at the lower end of said presser foot supporting bar, a blade mounted for reciprocating movement within said enclosing housing and having its cutting edge exposed at a slight overhanging angle immediately behind said work supporting horn, a pivotal bearing carried by said housing, and a walking beam connected at one end to the needle bar of the sewing machine and at its other end to said blade, whereby said blade will be caused to reciprocate Y in timed relation with the movement of a seam to be` ripped as the stitched seam isk advanced under said presser foot and over said horn by the operation of the sewing machine.

' 3. In a seam opening' device, the combination of a blade guiding means adapted to be suspended over a` work table, a blade movably mounted upon said guiding means with its cutting edge extending vertically and disposed outwardly from one side of said guiding means, means for imparting 'an operating movement to said blade, a horn-like seam guiding anvil projected outwardly from said guiding means at the lower end of said cutting blade over which material carrying a seam may be moved, said horn-like seam guiding anvil having a flared shoulder portion at its inner end adjacent said blade over which the stitched seam may be spread as the material carrying the seam is moved over said horn toward the cutting edge of said blade, and a guide means disposed over the outer end of said anvil for engaging the seam Icarrying material as it is moved over said anvil to the flared portion thereof.

4. In a seam opening device, the combination 'of a blade guiding support adapted to be suspended over a "work table, a movable blade mounted upon said support with its cutting edge exposed at one side thereof, means forimparting an'operating movement to said blade, a hornlike anvil projecting horizontally from said suppori; in alignment with the cutting edge of said blade and over which :a stitched seam may be spread to present the threads of the seam to the cutting edge of said blade, and a pair of spaced guide'members at the outer end of said horn-like anvil adapted and arranged to engage a seam carrying material at each side of the seam and align the seam with said blade as the material is moved along said anvil toward said blade.

RAY H. MCMURRAY.

REFERENCES CITED The following references are of record in the le of this patent:

Great Britain July 28, 1896 

